Method of purification and isolation of anthraquinone beta sulphonic acid



Patented May 11, 1926.

UNITED STATES PATENT "OFFICE.

IVAN GUBELMANN AND ROBERT J. GOODRICH, OF SOUTH MILWAUKEE, WISCONSIN,

ASSIGNORS TO THE NEWPORT COMPANY, OF CARROLLVILLE, WISCONSIN, A COR-PORATION OF DELAWARE.

METHOD OF PURIFICATION AND ISOLATION OF ANTHRAQIJ'INONE BETA SULPHONICACID.

No Drawing.

This invention relates to the purification and isolation ofanthraquinone beta sulphonic acid, also known as anthraquinone 2sulphonic acid, and more particularly to the purification and isolationof said acid from other products formed in the sulphonation ofanthraquinone. The chemical formula for anthraquinone beta sulphonicacid is:

In the production of anthraquinone beta sulphonic acid, as bysulphonation of ane thraquinone with sulphuric acid containing freeanhydride, any impurities present in the anthraquinone used aresubjected to thesame treatment. Furthermore, during the sulphonation,certain isomeric sulphonic acids; together with certain di-sulpihonicacids may be formed. The methodpf purification of the anthraquinone betasulphonic acid from these impurities has, in general, been bycrystallizing out the. sodium salt of anthraquinone beta sulphonic acid,known as silver salt, from the water solution of the sulphonation mass.Further purification of the silver salt is generally necessary byre-crystallization.

We have found that the ammonium salt of anthraquinone beta sulphonicacid can be crystallized and isolated in an exceedingly high degree ofpurity from a water solution of anthraquinone beta sulphonic acid, orits salts, and "accompanying impurities. The difierence in watersolubility under certain conditions of the ammonium salt ofanthraquinone beta sulphonic acid and of its common impurities is suchthat a high degree of purity and an elficient separation ofanthraquinone beta sulphonic acid may be accomplished in one treatment.

Furthermore, this "method provides a cheap and'rapid process for theproduction of pure anthraquinone beta sulphonic acid or its salts fromthe water soluble portion of the sulphonation mass. Diflerent degrees ofurification may also be effected by varying the conditions such asconcentration of the water solution, temperature, and by addmoniumsaltof said acid.

Application filed May a, 1925. Serial No. 29,236.

, cake with warm water until free of acid.

Concentrate the combined filtrate and wash to 9 Baum at 25 C. and addconcentrated aqueous ammonia until slightly alkaline. Heat to 90 (3.,hold one hour, and cool slowly to 25 C. After standing for twelve hours,filter offthe crystals of the ammonium salt of anthraquinone betasulphonic acid and dry the crystals at 100 C.

We are aware that numerous details of the process may be varied througha wide range a without departing from the spirit of this invention, andWe do not desire limiting the patent granted other than as necessitatedby the prior art.

We claim as our invention.

1. The method of purifying impure anthraquinone beta sulphonic acid andits salts which consists in converting said acid and salts into theammonium salt of the acid and isolating the ammonium salt.

2. The method of purifying impure anthraquinone beta sulphonic acid,which consists in dissolving said acid in water, converting said acidinto the ammonium salt and subsequently crystallizing out the am- 3. Themethod of purification and isola-' tion of anthraquinone beta sulphonicacid from the products of the sulphonation of anthraquinone', whichconsists in heating "a water solution of the sulphonation mass withammonia and allowing the ammonium salt of anthraquinone beta sulphonicacid to crystallize out. S

4. The method of purifying and isolating the ammonium salt ofanthraquinone beta sulphonic acid from Water soluble impurities, whichincludes dissolving the ammonium salt and impurities in water andrecipltating the ammonium salt of ant ra ties,- which includesdissolving, the ammo' nium salt and impurities in water and recipitatingthe a nnonium salt of anthranone beta sulpho ic acid by the addition ofwater soluble salts. I y

6. The method of purifying and isolating anthraquinone beta sulphonicacid from the water soluble products of the sulphonation ofanthraquinone, which consists in treating a water solution of thesulphona-tion mass with concentrated aqueous ammonia until slight- 1yalkaline, heating to approximately 90 C., cooling slowly to 25 0.,allowing to stand until crystallization is substantially complete, andfiltering off the crystallized ammonium salt of anthraquinone betasulphonic acid.

p In testimony whereof, we have hereunto subscribed our names.

' IVAN GUBELMANN.

ROBERT J; GOODRICH.

